Ordinarily, considerable human labor is required for the planting of nursery stock, such as tree or shrub seedlings, particularly on slopes or other irregular terrain. In planting the seedlings, it is first necessary to transport them to the planting site, clear the immediate planting area, dig a hole to proper depth for each plant, place the seedling in the hole, suitably moisten the plant, and then pack the soil around the plant root system to insure proper nourishment and growth of the seedling.
Various mechanical aids and planting devices have been proposed, but these devices have not been satisfactory mainly because they are not self-contained and because they cannot perform all the necessary steps in proper sequence and in a reasonably short time without considerable human supervision and labor. Also, in most cases the prior devices involve a considerable amount of individual handling of the seedlings in performing one or more of the required planting steps. Furthermore, use of the prior proposed planting machines is not practical on irregular terrain or on slopes.
A preliminary search of the prior art revealed the following prior U.S. patents of interest:
Miller, U.S. Pat. No. 2,520,809
Guigas, U.S. Pat. No. 2,749,855
Martin, U.S. Pat. No. 3,306,239
Huang, U.S. Pat. No. 3,712,252
Roths, U.S. Pat. No. 3,719,158
Dri et al, U.S. Pat. No. 4,091,751
Braun, U.S. Pat. No. 4,111,135
Westerhoven, U.S. Pat. No. 4,116,137